A display device using liquid crystals is light and thin with low power consumption as compared with a display device such as a Braun tube and therefore is widely used as a display device of a portable device, a computer, a large television, or the like.
On the other hand, liquid crystals themselves do not emit light and, therefore, in order to display a screen, a backlight unit is often required for emitting light from the back of the liquid crystals.
The backlight unit requires a backlight assembly which comprises light-emitting element boards comprising light-emitting elements such as LEDs (Light Emitting Diodes), a power supply board that supplies power and control signals to the light-emitting elements, and electrically conductive paths such as a harness that connect between the light-emitting element boards and the power supply board.
As a specific structure of the backlight assembly, there is, for example, a structure in which the light-emitting element boards and the power supply board are respectively fixed to the front and back of a chassis and the harness is passed through a hole provided in the chassis, thereby connecting the light-emitting element boards and the power supply board to each other through the harness (Patent Document 1).
In such a structure, however, the hole of the chassis should be filled up in order to prevent contaminants such as dust from entering the inside of the backlight unit through the hole of the chassis.
An example of such a structure will be described with reference to FIGS. 21 to 23.
As shown in FIGS. 21 and 22, a frame 3b is formed around an upper surface (front surface) of a chassis 3. Light-emitting element boards 23a to 23f each comprising light-emitting elements 31 such as LEDs and a light-emitting element connector 33 are screwed to the frame 3b (the light-emitting element boards 23e and 23f are not illustrated).
On the other hand, as shown in FIG. 23, a power supply board 137 that supplies power and control signals to the light-emitting element boards 23a to 23f is screwed to a back surface of the chassis 3 and power supply board connectors 135 are mounted on the power supply board 137.
The light-emitting element boards 23a to 23f and the power supply board 137 are electrically connected to each other through a harness 133. Specifically, the harness 133 comprises one-side ends forming light-emitting element side connectors 43 which are connected to the light-emitting element connectors 33, and the other-side ends forming power supply board side connectors (not illustrated) which are connected to the power supply board connectors 135.
The chassis 3 is provided with a hole 134 for passing the harness 133 therethrough.
The hole 134 is filled with a rubber plug 131 and the rubber plug 131 is provided with small slit-like holes 131a for passing the harness 133 therethrough.
As a method of assembling such a backlight assembly, the following processes are required.
(1) Attach the light-emitting element boards 23a to 23f to the chassis 3.
(2) Connect the light-emitting element side connectors 43 of the harness 133 to the light-emitting element connectors 33 of the light-emitting element boards 23a to 23f and lead out the harness 133 to the back side of the chassis 3 through the hole 134.
(3) Fill the hole 134 with the rubber plug 131.
(4) Fix the power supply board 137 to the back surface of the chassis 3.
(5) Connect the power supply board side connectors of the harness 133 to the power supply board connectors 135 of the power supply board 137.